\begin{figure}[htbp]
\centering
\subfloat[`左脚清明`]{
  \label{fig:subfig_a}
  \includegraphics{left.pdf}
}
\hspace{10pt}%
\subfloat[`右脚反复`]{
  \label{fig:subfig_b}
  \includegraphics{right.pdf}
}
\caption{`反清复明`}
\label{fig:subfig}
\end{figure}
